A coroner is calling for Rotorua's geothermal bylaw to be reviewed after two men died in motel hot pools.
The men, aged 77 and 88, died from hydrogen sulphide poisoning in separate incidents in 2007 and 2008 and were swimming alone when overcome by fumes.
Rotorua coroner Wallace Bain has recommended that people should never bathe alone and that where practicable the water should be stirred before use.
He is also calling for better ventilation, and more testing for hydrogen sulphide gas before swimming.
Dr Bain has also recommended more signs around pools advising swimmers of the risks.
He says the Rotorua District Council needs to look very carefully at what operating systems need to be in place for geothermal pools.
Dr Bain says while thousands of people have no problem, there is still a wildcard risk factor from swimming in hot pools.
The council's regulatory manager, Jim Nicklin, says some of the recommendations have already been adopted.
"Motel operators have already taken those initiatives on board, because in December of last year we wrote to them with some suggestions as to how better signage could be improved, around the pool complexes and certainly in room information for their guests, and they responded very positively to that."